[joeyg]

I am working on an addition and am installing a whirlpool tub. The tub requires 2 - 20 amp GFCI protect circuits: 1 for the pump and 1 for the heater. I ran 12/3 wire in the walls thinking I could have the BLACK wire go from 1 GFCI breaker to the pump outlet and the RED wire go from a 2nd GFCI breaker to heater outlet. What I failed to realize at the time was I only have 1 white neutral wire that would need to go to 2 GFCI Breakers.
Questions:
#1 Could I have the 1 white wire split in the electric panel and go to each of the GFCI breakers?
#2 I have seen 20 AMP Double Pole GFCI Breakers. Would this solve my problem?
My electric panel is a Cutler Hammer BR Box.
Thanks in advance for any suggestions.

Updated 6/23 @ 3:15.

#3 Someone I spoke to suggested another option.
Use a normal double pole breaker in the electric box. In the bathroom have the 12/3 wire run to a new double-gang box that is accessible (outside the tub). Here, use 2 GFCI Blank Face Receptacles (black to one, red to the other, share the neutral). Then run 2 sets of 12/2 wire from the 2 GFCI Blank Face receptacles to the outlets under the tub for the for the pump and heater.

[tkrussell]

The only way to wire this is to use 2 single pole GFI breakers and 2 runs of 12-2 with ground cable, creating one dedicated circuit for each unit.

There is no short cut for this situation.

GFI devices cannot operate on circuits with shared neutrals. The GFI measures the current in both the hot and the neutral, and compares them. IF the current flowing in the hot is 5 milliamps or more difference than the current returning on the neutral, it assumes a ground fault condition exisits, and trips off

So you can see why one breaker cannot monitor two circuits.

Sorry

Just noticed the added post. Yes using two blank GFI devices, and using two - 2 wire circuits from there will work. Same thing. One GFI for each circuit.

[labman]

I am not up on code enough to say positively that would be a violation. I certainly hope it is. I hope you haven't finished the wall yet, and can start over again with 2 separate 12-2 with ground lengths of wire. Remember, the neutral may be at ground potential, but it caries amp for amp the same current as the hot wire. You can feed 2 or more hot wires into the same neutral. Back before a few buildings burned down, it even met code. If both circuits carry over 10 amps, the neutral will be carrying over 20 amps with nothing to break the circuit and keep it from overheating.

[terryfitz]

The 2008 NEC simply states that on a split circuit where both hot conducters are yoked to the same device, that the circuit breakers have to be bonded together so that both are thrown at the same time. It is not true that a shared neutral would carry the 20 amps you mentioned. If one leg (say the red) carried 6 amps and the black had four, the neutral would only carry 2 amps. I suggest you follow through on how this works. Now since a GFCI breaker measures both the current flow between the hot and neutral and also monitors the ground for activity, a split circuit (3 conductor + ground) cannot work properly on a GFCI.

[stanfortyman]

First off, you are quoting the 2008 NEC. This thread is from 2005!

Now since a GFCI breaker measures both the current flow between the hot and neutral and also monitors the ground for activity, a split circuit (3 conductor + ground) cannot work properly on a GFCI.

This is completely wrong in two ways:

1) True, a GFI monitors current between the hot and neutral. It DOES NOT monitor ANYTHING with regard to ground. A GFI, especially a GFI breaker, will function prefectly fine even without a ground. In fact, a GFI device can replace a two-prong ungrounded receptacle.

2) A shared neutral circuit CAN work on a GFI. You must use a two-pole GFI breaker, which not only monitors the line to neutral current, it monitors the line to line current at the same time.

[hkstroud]

Tkrussel, stan

You say GFI breakers cannot share neutral. Does that also apply to GFI outlets?

[stanfortyman]

Well, I said a two-pole GFI breaker CAN be used on a shared neutral circuit.

As far as GFI receptacles that is a loaded question.
There are ways to wire it that they can, as long as only the LINE side is used.
You cannot load out of a GFI device with a shared neutral.

Once the shared neutral circuit is split up into two "2-wire" circuits then you can load out to other devices.

[hkstroud]

Thanks for clarifying. Acknowledge breaker statement not yours. Have to ask, what's GFCI Blank Face Receptacle? Why doesn't Joey just run 12/3 to a first GFI receptacle, use one circuit, pigtail neutral and 12/2 to second GFI receptacle. Throw breaker away. Also has to have a disconnect means there also doesn't he.

[mediumkahuna]

I'm with this guy: put a 2 pole GFI in your panel then connect pump and heater to same neutral that comes from 2 pole GFI

[donf]

Med -

Nice thought, however, this post is six years old and more than likely resolved by now.